/*

This file is part of Ext JS 4

Copyright (c) 2011 Sencha Inc

Contact:  http://www.sencha.com/contact

Commercial Usage
Licensees holding valid commercial licenses may use this file in accordance with the Commercial Software License Agreement provided with the Software or, alternatively, in accordance with the terms contained in a written agreement between you and Sencha.

If you are unsure which license is appropriate for your use, please contact the sales department at http://www.sencha.com/contact.

*/
/**
 * @class Ext.util.Memento
 * This class manages a set of captured properties from an object. These captured properties
 * can later be restored to an object.
 */
Ext.define('Ext.util.Memento', function () {

    function captureOne (src, target, prop) {
        src[prop] = target[prop];
    }

    function removeOne (src, target, prop) {
        delete src[prop];
    }

    function restoreOne (src, target, prop) {
        var value = src[prop];
        if (value || src.hasOwnProperty(prop)) {
            restoreValue(target, prop, value);
        }
    }

    function restoreValue (target, prop, value) {
        if (Ext.isDefined(value)) {
            target[prop] = value;
        } else {
            delete target[prop];
        }
    }

    function doMany (doOne, src, target, props) {
        if (src) {
            if (Ext.isArray(props)) {
                Ext.each(props, function (prop) {
                    doOne(src, target, prop);
                });
            } else {
                doOne(src, target, props);
            }
        }
    }

    return {
        /**
         * @property data
         * The collection of captured properties.
         * @private
         */
        data: null,

        /**
         * @property target
         * The default target object for capture/restore (passed to the constructor).
         */
        target: null,

        /**
         * Creates a new memento and optionally captures properties from the target object.
         * @param {Object} target The target from which to capture properties. If specified in the
         * constructor, this target becomes the default target for all other operations.
         * @param {String|Array} props The property or array of properties to capture.
         */
        constructor: function (target, props) {
            if (target) {
                this.target = target;
                if (props) {
                    this.capture(props);
                }
            }
        },

        /**
         * Captures the specified properties from the target object in this memento.
         * @param {String|Array} props The property or array of properties to capture.
         * @param {Object} target The object from which to capture properties.
         */
        capture: function (props, target) {
            doMany(captureOne, this.data || (this.data = {}), target || this.target, props);
        },

        /**
         * Removes the specified properties from this memento. These properties will not be
         * restored later without re-capturing their values.
         * @param {String|Array} props The property or array of properties to remove.
         */
        remove: function (props) {
            doMany(removeOne, this.data, null, props);
        },

        /**
         * Restores the specified properties from this memento to the target object.
         * @param {String|Array} props The property or array of properties to restore.
         * @param {Boolean} clear True to remove the restored properties from this memento or
         * false to keep them (default is true).
         * @param {Object} target The object to which to restore properties.
         */
        restore: function (props, clear, target) {
            doMany(restoreOne, this.data, target || this.target, props);
            if (clear !== false) {
                this.remove(props);
            }
        },

        /**
         * Restores all captured properties in this memento to the target object.
         * @param {Boolean} clear True to remove the restored properties from this memento or
         * false to keep them (default is true).
         * @param {Object} target The object to which to restore properties.
         */
        restoreAll: function (clear, target) {
            var me = this,
                t = target || this.target;

            Ext.Object.each(me.data, function (prop, value) {
                restoreValue(t, prop, value);
            });

            if (clear !== false) {
                delete me.data;
            }
        }
    };
}());

